Dho Yun-Sik, Kim Young Jae, Kim Kwang Gi, Hwang Sung Hwan, Kim Kyung Hyun, Kim Jin Wook, Kim Yong Hwy, Choi Seung Hong, Park Chul-Kee
1Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul.
2Department of Biomedical Engineering, School of Medicine, Gachon University, Incheon; and.
J Neurosurg. 2019 Jul 19;133(2):546-555. doi: 10.3171/2019.4.JNS1989. Print 2020 Aug 1.
The aim of this study was to analyze the positional effect of MRI on the accuracy of neuronavigational localization for posterior fossa (PF) lesions when the operation is performed with the patient in the prone position.
Ten patients with PF tumors requiring surgery in the prone position were prospectively enrolled in the study. All patients underwent preoperative navigational MRI in both the supine and prone positions in a single session. Using simultaneous intraoperative registration of the supine and prone navigational MR images, the authors investigated the images' accuracy, spatial deformity, and source of errors for PF lesions. Accuracy was determined in terms of differences in the ability of the supine and prone MR images to localize 64 test points in the PF by using a neuronavigation system. Spatial deformities were analyzed and visualized by in-house-developed software with a 3D reconstruction function and spatial calculation of the MRI data. To identify the source of differences, the authors investigated the accuracy of fiducial point localization in the supine and prone MR images after taking the surface anatomy and age factors into consideration.
Neuronavigational localization performed using prone MRI was more accurate for PF lesions than routine supine MRI prior to prone position surgery. Prone MRI more accurately localized 93.8% of the tested PF areas than supine MRI. The spatial deformities in the neuronavigation system calculated using the supine MRI tended to move in the posterior-superior direction from the actual anatomical landmarks. The average distance of the spatial differences between the prone and supine MR images was 6.3 mm. The spatial difference had a tendency to increase close to the midline. An older age (> 60 years) and fiducial markers adjacent to the cervical muscles were considered to contribute significantly to the source of differences in the positional effect of neuronavigation (p < 0.001 and p = 0.01, respectively).
This study demonstrated the superior accuracy of neuronavigational localization with prone-position MRI during prone-position surgery for PF lesions. The authors recommend that the scan position of the neuronavigational MRI be matched with the surgical position for more precise localization.
本研究旨在分析在患者俯卧位进行手术时，磁共振成像（MRI）对后颅窝（PF）病变神经导航定位准确性的位置效应。
前瞻性纳入10例需要在俯卧位进行手术的PF肿瘤患者。所有患者在同一次检查中分别于仰卧位和俯卧位接受术前导航MRI检查。通过同时进行仰卧位和俯卧位导航MR图像的术中配准，作者研究了PF病变图像的准确性、空间变形及误差来源。通过使用神经导航系统，根据仰卧位和俯卧位MR图像定位PF中64个测试点的能力差异来确定准确性。利用自行开发的具有三维重建功能和MRI数据空间计算功能的软件对空间变形进行分析和可视化。为了确定差异来源，作者在考虑表面解剖结构和年龄因素后，研究了仰卧位和俯卧位MR图像中基准点定位的准确性。
对于PF病变，在俯卧位手术前，使用俯卧位MRI进行神经导航定位比常规仰卧位MRI更准确。俯卧位MRI对93.8%的测试PF区域的定位比仰卧位MRI更准确。使用仰卧位MRI计算的神经导航系统中的空间变形倾向于从实际解剖标志向后上方向移动。俯卧位和仰卧位MR图像之间空间差异的平均距离为6.3毫米。空间差异在靠近中线处有增加的趋势。年龄较大（>60岁）以及基准标记靠近颈部肌肉被认为是神经导航位置效应差异来源的重要因素（分别为p<0.001和p=0.01）。
本研究证明了在俯卧位手术治疗PF病变时，俯卧位MRI神经导航定位具有更高的准确性。作者建议，为了实现更精确的定位，神经导航MRI的扫描位置应与手术位置相匹配。
